Closure cap and method of making



Aug 8, 1939. J. c. GIBBS 8 6 CLOSURE CAP AND METHOD OF MAKING FiledMarch 17, 1936 INVENTOR (70% a (110w i M ATTORNEY Patented Aug. 8,,l939-UNITED I STATES 1 ATENT OFFICE I v onosrma can 13320 01 John 0. Gibbs,Brooklyn, N. Y., assignor to Anchor Cap & Closure Corporation, LongIsland City, N. Y., a corporation of New York Application March 11,1936, Serial No. 69,286 a 3 Claims. (or. 113-121) The present inventionrelates to the production of closure caps and more particularly to screwclosure caps and an improved method of making such caps.

Packers and bottlers are greatly'interested in the appearance of theirpackages, which may be impaired or enhanced by the closure cap used forsealing the packages. Packages, are, for the most, part, purchased byhousewives, who are guided in their purchases to a considerable extentby the attractiveness orbeauty of the package. Various attempts havebeen made to obtaincaps which are attractive in appearance. Closure capsmolded of phenolic condensation products and other synthetic resins ormolding compounds have become quite popular due to their attractiveness.This popularity was attained i-nspite of the fact that the closures donot form a better seal, are more expensive, and are subject to breakagebecause of their frangible nature. Various attempts have been made tomake metal caps which would have the attractiveness of moldedcapswithout the disadvantages. One solution was to utilize two nestedmetal caps, the inner cap serving as the sealing'cap and the outercap asa cover cap or shell to conceal the screw threads or container engagingmeans and other irregularities of the inner cap. Such caps are subject.to the objection of increased cost, due to the extra closure or covercap, and due to the extra operations necessary in manufacturing andassembling the caps. In addition, occasionally the two closures rotatewith respect toeach other, which prevents the cap from being unscrewedfrom a container and properly applied to form a seal. Plain skirted capshave also been made by turning the edge of the cap inwardly and forminglugs or short thread projections from the inturned edge or bead. Themethod of manufacturing such caps increases the cost. In addition, suchcaps cannot be applied to a. container provided with a continuous threadfinish. The latter finish is more. prevalent and is frequently demandedby the packer or bottler for certain types of packages.

The present invention aims to provide an inexpensive closure cap adaptedto fit on a continuousthread finish having the advantages of molded anddouble shell caps without having the disadvantages of either. Theinvention aims further to provide an inexpensive practical method ofmaking the caps, which decreases their cost and improves theirappearance by eliminating with concealed threads on the interiorthereof.

is the first step of forming the cap;

Another object of the invention'is to provide an improved method forforming thread engaging means on the inside of the capwlthout'reforining the exterior thereof.

Another object of the invention is to reduce the cost of manufacturingmetal screw caps having a plain skirt.

Another object of the invention is to provide a practical method ofmaking screw caps having a concealed thread. Other and further objectsof the invention will be obvious upon an understanding of theillustrative embodiment about to be. described, or will be indicated inthe appended claims, and various advantages not referred to herein willoccur to one skilled in the art upon employment of the invention inpractice.

A preferred mbodim'entof the invention has been chosen for purposes ofillustration and de-' scription and is shown in the. accompanyingdrawing, forming a .part of the specification, wherein- Fig. 1 is asectional view illustrating a blank after it is'stamped from a sheet ofmetal, which Fig. .2 is a sectional view illustrating the sec ond stepof a method of forming the cap;

Fig. 3 is a sectional view illustrating the third step in forming thecap;

Fig. 4 is a perspective view illustrating a com pleted 7 cap;

Fig-5 is a fragmentary side elevational 'view, partly in section, of aglass container with the cap shown in Fig. 4 sealed thereon:

Fig. 6 is'a sectional view illustrating the second step in anothermethod of forming a cap;

Fig. 'I is a fragmentary sectional view of a. cap finished from theblank shown in Fig. 6;

Fig. 8 is a fragmentary sectional view of a finished cap, the shape ofthe blank after the second step of manufacture being indicated in dottedlines; r r Fig. 9 a fragmentary sectional view of a cap illustratinganotherembodiment of the invention, the shape of the blank after thesecond step of manufacture being indicated in dotted lines; and Fig. 10is a fragmentary sectional view ,of acap illustrating still anotherembodiment of the invention, the shape of the blank after the secondstep being shown in dotted lines.

Referring again tothe drawing, and more particularly to Figs. 4 and 5thereof, there is shown a closure cap made of sheet metal such astinplate, aluminum or the like, having a cover portion I and a dependingskirt or flange 2. The lower edge of the skirt has a slit or slot 5therein and is turned inwardly and upwardly, as shown at 4.

The slot 5 is provided to facilitate the formation of the skirt of .thecap and particularly i the folding of the lower edge thereof. A screwthe purchaser or manufacturer.

thread 6 is formed in the inturned part 4 of the skirt by a groove 1having a convex surface 8 facing inwardly toward the center of the cap.

It will be understood, of course, that the thread sufficient to bevisible from the exterior of the cap. In this way, the raw edge formedby cutting the slot is concealed within the skirt of the cap and thelower edge of the skirt of the finished cap is smooth andunmarked.

In Fig. 5 the cap illustrated in Fig. 4 is shown sealed to acontainerhaving a continuous thread 9. The thread 6 of the cap fits under thethread 9 of the container to hold the cap on the container and tocompress a sealing liner between the cover of the cap and the rim of thecontainer.

The liner is usually assembled with the cap and may be'made ofcardboard, cork, rubber, or the various other types of sealing material.It may also be in the form of a ring of similar material, if desired,the function thereof being to form a liquid-tight or hermetic seal. Thecap is screwed on the container in the same manner as other types ofscrew caps. The exterior of the cap, however, is preferably plain, withthe screw thread 6 invisible, as shown. It will be understood, however,that the cover of the cap or skirt may be shaped to conform to the tasteof Such shaping of the skirt may be independent of and free from thedeformation necessaryin the formation of the thread.

A method of forming the closure described above is illustrated in Figs.1 to 4. The blank shown in Fig. 1 may be stamped from a sheet ofdecorated metal and the slot may be formed simultaneously therein by thesame operation.

The length of the skirt may be uniform throughout the circumference oras in the embodiment described hereinafter it may be of a varyinglength. In'the second step, the lower portion of the skirt is turnedupwardly and inwardly into the cap to form a hollow head, as shown inFig. 2. This may be accomplished in any suitable manner, for example, bya curling or a rolling operation, but the former is preferred. Ifdesired, the lower edge of the skirt may be bent inwardly slightly priorto the second operation as shown in dotted lines in Fig. 1 to facilitatethe rolling or curling operation. Thereafter, in the third step, asshown in Fig. 3, the bottom portion 4 of the skirt 2 forming the bead isreformed to provide the groove 1. The die members in Fig. 3 are shownapplied to a cap with the cap in its upright position. In normalmanufacturing operations, the cap would preferably be in inverted oredgewise position and the position of the dies changed accordingly.Preferably, the third step is performed by placing the cap blank into acup-shaped die A conforming to the outer contour of the cap and engagingdie B having a helical portion H thereon adapted to push portions of thebead upwardly and outwardly against the skirt to reform the bead into athread. While to support the upper convex edge 8 of the bead.- The anvilC preferably is in the form of an expandibie chuck comprising severalsegments adapted to be expanded against the inner walls of the skirt andto be contracted for inserting and withdrawing the chuck past the threadportions. The lower edge of the anvil chuck C is provided with helicalportions l2 corresponding to the helical thread forming portions ofthedie member B. The helical portions'of the dies B and C determine theinclination of the thread and the position of the thread with respect tothe lower edge of the skirt. The die B preferably has a groove I3therein adapted to receive the lower edge of the skirt to maintain theshape of the lower edge and press the lower portions of the upwardlyfolded bead against the inner side of the skirt. In this manner both theouter skirt portion andthe inturned part 4 are rigidly supported andreinforced and the groove l is positioned in the interior of .the skirtto provide the thread 6.

The slit 5 plays an important function in the method and in theresulting cap in that it permits the inturned portion 4 to be foldedinwardly and upwardly by a bending or folding operation. Without theslit 5, it would be necessary for the lower edge of the cap to becompressed during the reforming operation. During such compression thereis a tendency for the metal to wrinkle and the operation is otherwisedifiicult and expensive. The present closure may be formed by a simplebending operation which minimizes the strain on the metal and which doesnot impair the lacquer. The, operation is sufficiently simple so thatthe groove or thread, if desired, may be formed in the blank before themetal is turned inwardly, as illustrated in Figs. 6 to 10. While the diemembers A and B and the chuck C are illustrated diagrammatically, itwill beunderstood that they may be in any desired form and are adaptedto be associated with any desired automatic cap fabricating machine.

The cap shown in Fig. '7 is similar to the one shown in Fig. 4 and maybe made by a similar method. The helix angle of the thread 6 is obtained by making the skirt 'of the blankbf uneven length, preferably thebottom of the skirt being in the form of a spiral conforming to thehelix angle of the thread desired. A groove 1 is then formed, as shownin Fig. 6 at the bottom of the skirt which has a spiral formation sothat the convex side of the groove, when turnedinto the cap as shown inFig. 7 will form a thread 6' of the proper helix angle. Preferably, theformation of the groove 1' is uniform throughout its length. In Fig. 'Ithe lower edge of the skirt is shown folded into the cap so that thethread extends radially inwardly from'the inner side of the skirt. Thisoperation may be accomplished by a suitable curling die B while a chuckC is utilized tosupport the upper edge of the thread.

thread within prescribed tolerances, but may be omitted. It will beunderstood also that the cap shown in Fig. 7 may be made by the methodillustrated inFigs. 1, 2 and 3.

The cap shown in Fig." 8 may be formed from a blank of uniform lengthand the groove I may b rolled into the blank as shown in dotted lines inFig. 8 before the edge is folded inwardly and upwardly. The groove, atthe time of the formation, has the proper helix angle to form a suitablethread 6' when it is turned in.

I perfect sealing results and has suflicient-resil- The cap sh own inFig.9 is preferably formed from a blank having a skirt cut at a helixangle corresponding substantially to the helix angle of the thread onthe container, and the lower edge of the skirt of the blank is rolledoutwardly and upwardly into "a wire edge It, as shown in dotted lines inFig. 9'. of the skirt is folded inwardly as shown at l5. with the wireedge It forming-the thread for the cap. With the aid of the notch orslit in the skirt of the cap, the lower edge of the skirt having thewire edge formed on it may be folded into the interior of the skirtwithout difllculty. It will be understood that the plurality of notchessimilar to the notch 5 may be utilized, if desired.

In Fig. the formation of the cap is similar to that in Fig. 9 exceptthat the lower edge of the blank is rolled inwardly into abead IS on a Ibead is a more diflicult operation than rollinghelix angle andthereafter the entire bottom part I of the skirt is folded upwardly intothe cap to provide a thread. The rolling inwardly of the outwardly, butit may be advantageous in certain cases. In the formation of the caps ofFigs.- 9 and 10, the skirt of the blank may, if desired, be of uniformlength and the helix angle may be obtained by rolling the rolled edge-onthe blank more at one point than at another to obtain the helix angleand thereafter turning the bottom of the skirt inwardly and upwardly tocomplete the cap as described above. i

. It will be understood, of course, that'in the formation of the presentcap it may be desirable, in some instances, to perform certain of theoperations after the loweredge of the metal has been folded inwardly.For example, it may be desirable to roll or otherwise further compressthe bottom edge of the skirt so that the infold'ed bottom portion 4 willbe in closer contact with. the skirt 2.,

In the manufacture and sealing of metal 010- sure caps, the caps aremade in a cap factory and the containers in a glass factory. Preferably,the liner I0 is assembled in the capby automatic machinery and shippedin assembled state. The packer. may dump the caps .into the hopper of anautomatic machine,'which will apply them to the containers or he mayscrew the caps on the containers by hand. The housewife removes the capmanually by unscrewing it. The construction of the cap is such that awide range of variations in the size of the glass container can beaccommodated without the cap being difiicult to apply or remove. Theformation of the thread gives greater resiliency and more holding powerthan is present in the ordinary types of screw caps. The thread by theskirt, eliminates relative movement between. it and the skirt and bybeing formed by metal turned inwardly and upwardly, provides a supportfor the liner l0 and prevents it from falling out of the cap.

It will be seen that the present invention pro-- Thereafter, the bottombeing an integral part of iency and flexibility to accommodate thevariations in the size of glass containers. The slot in the bottom ofthe skirt blank permits the metal to be folded inwardly without materialstrains on the metaLor marringthe lacquer or coating. The'slot alsopermits the/end of the container thread to pass .between the respectiveends of the cap thread so that the cap thread may be screwed under thecontainer thread. The cap has all the advantages in appearance of amolded or a double shell cap and eliminates the disadvantages of each. h

As various changes may be made in' the form, construction andarrangement of the parts herein without departing from the spiritvandscope of the invention and without sacrificing any of its advantages, itis to be understood that all matter herein is to be interpreted asillustrative and\ not in a limiting sense.

' 20 Having thus described my invention, I claim:

1. The method or making closure caps, which method comprises forming ablank having a 'cover portion and a depending skirt, slitting the .loweredge of the skirt, folding the lower portion of the skirt inwardly andupwardly to form a bead interrupted at one point by said slit, andcompressing said head by means of two dies having opposed complementaryhelical surfaces designed to engage the bead, thereby to form a helicalthread, the relative positions of the dies and the slit in the cap beingsuch that the thread .in the cap begins and ends on the respective'sidesof the slit. T

2. The method of making closure caps, which method comprises forming ablank having a cover portion and a depending skirt, slitting the loweredge of the skirt, folding the lower portion of the skirt inwardly andupwardly to form an inturned bead interrupted at one point by said slitand compressing said bead ing opposed complementary helical surfacesdesigned to engage the bead thereby to force certain portions of'thebead outwardly against the wall of the closure to form a helical threadfrom other portions thereof, the relative positions of the dies and theslit in the cap being such that the thread in the cap begins and ends onthe respective sides of the slit.

- edge thereof, said inturned bead having one vertical slit thereinconcealed from view by the skirt of the cap when viewed from theexterior, the ,lower portion of said inturnedbead being flattenedagainst the skirt of the cap throughout the circumference of the skirtto provide a continuous thread in the cap by afold of metal in theinturned bead, said fold being compressed to provide a helical threadadapted to engage a thread on the container which extends substantiallyentirel'y about the skirt of the cap, commencing at one side of saidslit and terminating at the other side of said slit,thereby-facilitating entry of a container thread between-the ends ofsaid cap thread at said slit, said thread having a substantiallyconstant width and depth throughout its length.

JOHNC. GIBBS.

40 by means of two dies hav-

